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SubjectFree lesson

Data processing II

ClassNotes Team 4 MIN READUPDATED 29 JUN 2026

Computer Science JSS1 Second Term

WEEK  2

Data processing II

Performance Objectives

The student should be able to

     1. State the stages of data processing.

     2. Describe what each stage entails.

Content

Data Processing Cycle 

Data processing cycle includes:

1. Data gathering: At this stage, data is gathered through various ways such as asking questions, observations, reading books, listening and watching electronic media (radio and television). For example, giving a prospective customer a form to fill before opening a bank account is a form of data gathering.

2. Data collection: This involves writing out, sorting, summarizing or classifying data into groups, structures or files. Data is sorted in a way that will make data processing easy. Data collection is a term used to describe a process of preparing and collecting data. The purpose of data collection is to obtain information to keep on record, to make decisions about important issues, to pass information on to other. Primarily, data is collected to provide information regarding a specific topic. 

3. Input stage: At this stage, all information collected is entered into the computer through an input terminal (eg. mouse, keyboard, web camera etc). Input devices are devices that accept data in its original format, examples includes keyboard and mouse. Data is entered through input devices. This is the process through which collected data is transformed into a form that computer can understand. It is a very important step in the data processing cycle because correct output result totally depends on the input data. Three steps are involved when inputting data into the computer: 

i Collection: This refers to gathering the data from a variety of sources and assembling it. 

ii Verification: This means checking the data to determine whether it is accurate and complete, and if it should be included for processing. 

iii Coding: This is translating the data into machine-readable form. Data punched into IBM cards is one example of coding.

4. Processing stage: During processing or manipulation, one or more of the following tasks may be performed on the input data.

i Classifying: Data are organized by characteristics meaningful to the user. For example, a student may be identified by the admission number and class.

ii Sorting: In this step, the data may be arranged in a particular sequence to facilitate processing.

iii Calculating: Calculations may be required to determine a patient’s account balance or a student’s grade point average.

iv Summarizing: This involves reducing a large document into a smaller size containing important points. At this particular stage, data is converted (processed) into information. 

5. Storage stage: All computers need to store and retrieve data for processing. Storage can be grouped into two categories:

i Primary storage: The primary storage, also called main memory or Immediate Access Store (IMAS) resides in the computer. This is necessary since the processing unit can only act on data and instructions that are held in primary storage. Primary storage consists of two types of memory chips. These are Random Access Memory (RAM) and Read Only Memory (ROM) chips.

ii Secondary storage: This is needed to store data and information on a permanent basis for later use. Examples of secondary storage devices are floppy disk, hard disk, zip drives, flash drives etc.

6. Output stage: After completing the processing step, output is generated. The result of the data processed is printed out from the printer.  Mostly, the output is stored on the storage media for later use. If the output result is accurate, the data processing cycle is completed. Output activities include the following;

i Retrieving: This involves pulling information from storage device for use by the decision-maker.

ii Converting: This means translating information from the computer form used to store it, to a form understandable by the user (such as, a CRT display or printed report).

iii Storing: This involves transferring the data onto a storage medium, such as a disk or tape file for future use.

iv Communication: This takes place when the relevant accurate information is in the right place at the right time.